Treason is not taken kindly even if it's just a joke.

Doing some husband-hunting, Iku?

[deleted]

Next stop: Letty's

This actually gives a clue to a long-standing question: how much do the osa-yukkuris understand of what's being said by the regular Touhouites?

In this case, them understanding Iku's joke about finding her a husband (even if they don't realize it is a joke) says the level is pretty high.